Current and historical procedures for the treatment of colon and rectal cancer have been based, for staging purposes, upon the natural history of tumor spread, and thence, upon operative and non-operative options. Operative options generally have looked to the physical location and surgical resection of tumor. A variety of techniques have been brought to bear in the art with the purpose of aiding the surgeon in detecting and localizing neoplastic tissue as part of this surgical procedure. ("Neoplastic tissue", for present purposes, often is referred to as cancerous tissue, though malignant tumor and malignant tumor cells also are found in the terminology of the art. The term "neoplastic tissue" includes all of these.) A substantial amount of effort in aiding the surgeon in locating neoplastic tissue has been through the utilization of radiolabeled antibody for detection purposes. For example, one technique includes the scintillation scanning of patients injected with relatively high energy, e.g. .sup.131 I labeled antibodies. Such photoscanning or scintillation scanning provides scintigrams difficult to interpret because of blood pool background radioactivity. Computer subtraction of radioactive blood pool agents and the use of two labeled antibodies (one specific for the tumor and one non-specific) have been attempted to enhance imaging. Nevertheless, such techniques have been found to provide little, if any, useful information to the surgeon, especially over and above CAT scans, magnetic resonance imagings, and like traditional techniques. Typically, large tumor is readily located by the surgeon by visualization at the operating theater and, in particular, through palpation, i.e. the feel of a tumor as opposed to that of normal tissue. To achieve operative success, however, it is necessary for the surgeon to somehow locate "occult" tumor, i.e. tumor which cannot be found by the conventional surgical procedure of sight and feel. Failure to locate and remove such occult tumor generally will result in the continued growth of cancer in the patient, a condition often referred to as "recurrent" cancer. In general, conventional diagnostic techniques as, for example, use of the classic gamma camera and the like, fail to find or locate occult tumor. As tumor sites become smaller, the radionucleide concentrations at a given tumor site will tend to be lost, from an imaging standpoint, in the background where blood pool radiation necessarily is present in the patient.
U.S. Pat. No. 4,782,840 by Martin, M.D. and Thurston, Ph.D., entitled "Method for Locating, Differentiating, and Removing Neoplasms, issued Nov. 8, 1988 (the disclosure of which is expressly incorporated herein by reference) reviews such scintillation scanning technique and discloses a much improved method for locating, differentiating, and removing neoplasms. Such technique utilizes a radiolabeled antibody and a portable radiation detection probe which the surgeon may use intraoperatively in order to detect sites of radioactivity. Because of the proximity of the detection probe to the labeled antibody, the faint radiation emanating from occult sites becomes detectable, for example, in part because of the inherent application of the approximate inverse square law of radiation propagation. The procedure is known as the Radioimmunoguided Surgery.TM. system (RIGS) (Radioimmunoguided Surgery and RIGS being trademarks of Neoprobe Corporation, Columbus, Ohio) and is successful additionally because of a recognition that tumor detection should be delayed until the blood pool background of circulating radiolabeled antibody has had an opportunity to be cleared from the body. As a consequence, the photon emissions or radiation emitted at minor tumors compared to surrounding tissue becomes detectable in view of the proximity of the probe device to it. Fortuitously, the '840 patent discloses the ability of the radiolabeled antibody to remain bound to or associated with neoplastic tissue for extended periods of time with the radio tag still bound thereto. Moreover, even though the accretion of radioactivity at the tumor site decreases over time, the blood pool background and surrounding tissue (relative to the tumor sites) decrease at a much greater rate so that the radioactive sites can be determined readily utilizing a hand held probe positioned in close proximity with the tissue tender investigation.
Colonic tumor generally originates at the mucosa or inner layer of the bowel. Because of this interluminal location, i.e. within the interior of the colon, early primary tumor cannot be seen or visualized by the surgeon. Thus, the conventional palpation or "feeling" procedures generally are employed to locate the otherwise hidden neoplasm. Visualization of tumor at the exterior surface of the colon only becomes available as a detection technique when the tumor will have grown or matured to an extent that it extends outwardly through the wall of the colon and, thus, its presence is apparent. One approach to locating the position of essentially hidden tumor or localizing a hidden lesion has been resort to intraoperative colonoscopy. This technique exhibits drawbacks due, in part to a requirement for the insufflation of air into the colon with attendant luminal distension, making subsequent surgery more difficult. In this regard, the technique has a potential for engendering toxicity and breaking the sterile field. Additionally, the added procedure increases anesthesia time, total operating room time, and operative costs.
Tumor which is evidenced or "recurs" following earlier surgery typically is diagnosed by the occurrence of elevating CEA levels (carcinembryonic antigen). Generally, this recurring cancer is, in effect, hidden cancer which was not found in earlier surgery and now has commenced to mature. The carrying out of a second surgical procedure, a procedure sometimes referred to as "second look" surgery, has been the subject of study. A high morbidity rate is associated with such procedure. Often the procedure essentially is an "open and close" one, the patient exhibiting severe metastisis not otherwise detectable and not surgically treatable. This determination of unresectability through open surgery, of course, is attended with severe trauma to the patient.
A highly important aspect of all procedures associated with colorectal and other cancers resides in the proper staging of the patient according to the extent and severity of the disease. Such staging aids in determining the appropriate post-surgical treatment for such patients. Stage I and II patients are believed to be curable by surgery alone, whereas Stage III patients, i.e. patients determined to have cancer spread to the lymph nodes, are treated with some form of post-operative therapy, such as chemotherapy. Stage IV patients, i.e. patients with metastisis to other organs, are treated with a variety of methods, including post-surgical therapy and/or surgical removal of the primary tumor. More severe metastisis typically is not deemed to be treatable by surgery and thus, surgery is not undertaken in order to spare the patients unnecessary trauma. Where the above-noted hidden or occult cancer is not found, residual disease is left behind and is not accounted for with respect to an evaluation of the extent of the disease to determine proper post-surgical therapy.
The contribution of RIGS-based surgery to enhancing the vision-based and touch-based procedures of the surgeon has been substantial. The detection and location approach of this system has permitted the identification and removal of hidden or occult tumor under conditions where otherwise conventional procedures would not have found it. Additionally, the system has been employed in staging, particularly in evaluating lymph nodes and other metastatic disease for staging procedures. The system has been demonstrated in clinical studies to substantially improve the staging of primary colorectal cancer patients which, having been staged by traditional means, were restaged to State III disease based upon the RIGS system as confirmed by pathology findings. As a consequence of such findings, patients so re-evaluated are eligible for post-surgical therapy, such as chemotherapy, resulting in improved patient management. The importance of such staging has been established in view of the National Institute of Health (NIH) consensus report concerning the administration of adjuvant chemotherapy to appropriately stage patients. "NIH Consensus Conference: Adjuvant Therapy for Patients with Colon and Rectal Cancer", JAMA, 1990; 264: 1444-50.
Somewhat recently, laparoscopic surgery (minimal access surgery) has become popular as an alternative to traditional open surgery procedures. Particularly with the development of video-based visual systems, laparoscopic surgical techniques have been employed with more complicated gastro-intestinal procedures. Such procedures look to savings in total health care costs as a result of shorter hospital stays and a more rapid patient return to normal activity. However, these procedures require instrumentation and technique supplanting conventional three-dimensional viewing and tactile feedback to the surgeon. Improved instrumentation particularly is called for where these newer surgical techniques are applied to the detection and removal of neoplastic tissue.
While a variety of laparoscopic instruments have been developed, such equipment falls into two broad categories: those major pieces of equipment that enable the surgeon to perform laparoscopy and those instruments related to the performance of specific tasks or procedures, e.g. electrocautery and laser. Generally, visualization within peritoneal cavity requires "space" in which to shine light and maneuver. In a standard surgical approach or laparotomy this space is created by opening the abdomen and allowing room light and air into the cavity to accommodate three-dimensional viewing. In laparoscopic procedures, this is accomplished by filling the peritoneal cavity with a gas that distends the abdominal wall and provides an area for light and manipulation, a process termed "pneumoperitoneum". Carbon dioxide currently is the standard gas used for pneumoperitoneum. Pneumoperitoneum typically is carried out utilizing an instrument referred to as an insufflator.
Laparoscopic surgery generally features the establishment of one or more portals of entry into the abdominal cavity. Mechanisms for inserting and removing various instruments through these portals without loss of pneumoperitoneum are necessary. These ports are established by the insertion of a trochar tip through the skin of the patient in conjunction with a port defining cannula or sheath. The trocar is inserted through the lumen of the cannula as an obturator. Typically, the cannulas have a spring-loaded trumpet valve to permit the introduction of instruments into the abdomen and prevent gas from escaping. Conventionally, the size of the cannula sleeve is 1 mm larger in diameter than the corresponding instrument that will traverse it. Diameters for such instruments may reach, for example, 15 mm or larger in extent.
Employment of the laparoscopic surgical technique in conjunction with the surgical staging and resection of neoplastic tissue poses limitations heretofore not encountered by the surgeon. With laparoscopic surgical procedures, sight is constrained to the two dimensions available at a video screen and palpation or feel essentially is lost. In effect, the surgeon is maneuvering along or manipulating tissue through elongate instrumentation from a distance of about 18 inches away.
Where a primary tumor has not developed through the wall of the colon or is in regions of the color unaccessible to the camera, it will not be seen by video imaging. Finding this tumor by palpation is not an option available to the surgeon. The constraints associated with lesion demarcation by intraoperative colonoscopy remain, and the procedure often calls upon the surgeon to strategically guess as to tumor location. Where such uncertainty is present, an opportunity for cutting into neoplastic tissue itself is present, a situation representing a potential for peritoneal spread of tumor, or seeding.
The current limitations of laparoscopic or laparoscopic assisted colon surgery also impose severe limitations in carrying out staging of the disease. This again is due principally to the exploratory constraints imposed by the surgical approach wherein lymph node metastisis involvement cannot be adequately evaluated. In this regard, visualization alone of the lymph system using laparoscopic video instrumentation generally will not be achievable, or if achievable will not locate positive or cancerous lymph nodes or other metastatic disease.
Should this minimal access surgery be developed to overcome the above-discussed severe limitations, important advantage may be evolved with the procedure. In this regard, the approach promises a diminished post-operative pain which minimizes the need for narcotic analgesia. The procedure allows patients to resume an oral diet faster, and gives the patient a shorter hospital stay and a more rapid return to normal activities. Some investigators are of an opinion that the incidences of post-operative complications such as atelectasis and pneumonia, deep venis thrombosis, wound infections, and the like are less with the laparoscopic approach.